Acentech

Falmouth Wind Turbine Options Analysis Process
Sound Mitigation Options Review and Recommendations
24 July 2012
Meeting 8
Eric W. Wood and James D. Barnes
Acentech
Acentech Background
Acoustical Consulting Spanning 60 Years
Research Firms, Electric Utilities, Architectengineers, Commercial and Industrial Developers,
Environmental Consulting Firms, Equipment
Vendors, Government Agencies, and Homeowners
Acentech
Response to Two Earlier Comments
Someone here suggested that Acentech works only with
developers, owners, and operators of industrial facilities.
For your consideration, I offer the following examples
of several Acentech clients and projects:
Acentech
Examples of Acentech Consulting Assignments
Not for Facility Developers or Owners
Town of Belmont, NH
Town of Richmond, RI
Homeowner in Billerica, MA
Attorneys General Office, NH
Cape Cod Commission, Bourne, MA
Town Engineer and Planning Board, Cohasset, MA
Department of Environmental Protection, Boston, MA
National Academy of Sciences, Washington, DC
DOD: Divers, Carrier Deck Crews, and Tinnitus
Acentech
Acentech consultants bring to this group experience,
qualifications, and understandings gained from serving a
wide range of clients, not just industrial developers.
We also bring important professional and personal ethics.
I will be pleased to receive questions if additional
information is wanted about this important topic.
Acentech
During a previous meeting here someone mentioned that
my colleague Jim Barnes made some observations and
sound measurements at 211 Blacksmith Shop Road
during the afternoon of Saturday 19 February 2011
Acentech
Acentech Report Submitted 15 March 2012
Brief Summary
Many options have been suggested for addressing
concerns about sound from the wind turbines
Some are highlighted in the following slides
Acentech
Should this group consider criterion (goals) for the wind
turbine sound at nearby residences in Falmouth?
Mass DEP Guideline: Background Sound + 10 dBA
Town of Falmouth Criteria: “There shall be a rebuttable
presumption that noise from the windmill in excess of 40
dba, as measured at the property line, shall not be
excessive.”
Or perhaps a different sound level goal
Acentech
Might it be reasonable to offer financial
compensation to the nearest neighbors?
For example:
Acentech
Offer to purchase noise easements at
selected nearby properties, or
Offer to purchase at full fair-market value selected
properties and then resell the properties with an
appropriate easement.
Costs and time subject to negotiation
Acentech
Curtail operations during selected periods,
such as summer nighttimes.
Consider both wind direction and wind speed
when planning curtailment periods.
Costs of lost energy depend on periods selected.
Can be estimated by the Town
Acentech
Document sounds during the full range of weather
and operating conditions for an extended period,
with and without wind turbine operation.
Amplitude-modulated sound
Low-frequency sound
Infrasound
Compare sounds from Wind 1 and Wind 2
with sounds from other wind turbines.
Costs and time depend on periods selected.
Acentech
Perform additional measurements to check
if the wind turbine sound complies with
the Vestas reference values.
Cost would be modest and could be done soon.
Acentech
Consider the application of sound masking at the wind
turbines or at selected nearby residences.
This could address the amplitude-modulated “whoosh –
whoosh” sounds mentioned by some neighbors.
At homes, costs would be modest and could be done soon.
At the turbines this would be a development project.
Acentech
Consider the application of active noise control at
the wind turbines or at selected nearby residences.
This would require a development project.
Costs and time to be determined.
Acentech
Offer to upgrade the outdoor-to-indoor sound insulation
of selected nearby residences.
Provide modest sound reduction inside selected homes.
Costs could be estimated.
Probably the order of $45,000 per house.
Indoor sound reduction only.
Acentech
Consider blade modifications such as
serrated trailing edges. Relatively simple technology.
2 dBA sound reduction reported for another site
with GE wind turbines. Costs not reported.
Acentech
Serrated Trailing Edges Installed
Acentech
Perform cost-benefit analysis of mitigation options.
Evaluate perceived balance of the costs and the benefits
for alternative mitigation options.
Acentech
Consider watching the movie with alternate perspectives
about the Vinalhaven Island Wind Turbines
“Islands in the Wind”
available to view online at:
http://www.youtube.com/watch?v=5I6F1-1sJa0
Acentech
CBI slides from meeting six includes questions for
Option 6 Noise Control and Option 7 Economics
What is the noise issue? Component characteristics?
Qualitative and quantitative measures of noise impacts?
Factors that determine which properties?
Acentech
From my1977 Paper “The Sound of Low-Speed Fans”
Acentech
There is a wide range of sensitivities to noise.
From very sensitive to very tolerant.
See below early study by my colleague Ted Schultz.
Acentech
Thank you for inviting me to your group meeting
I will be pleased to respond to questions
and requests for additional information.
Acentech